LLY: Possible Bad Injector?

[cstephens93]

Yesterday I was driving down the road on cruise control at about 45mph and felt my truck start to what I thought felt like a slight sputter. I also started to hear a faint knocking/ticking sound at mid throttle.

It doesnt make this noise consistently throughout my entire drive, just intermittently.

This morning I tried to take a video so I could capture the sound.

Truck was also feeling like it was sputtering as well.

No smoke noticeable and no codes thrown

https://www.youtube.com/watch?v=wAbpcDWzaiY&feature=youtu.be

 

[cstephens93]

Also, is there a simply way to diagnose which injector it may be with a V2?

 

[six5creed]

My truck does that every now and then, I was told on here probably a bad FPR and been adding 2 stroke oil and it hasn't done it in a while.
I use the stuff in a blue jug from Wal-Mart TC-W3 and mix it 200:1

 

[cstephens93]

My truck does that every now and then, I was told on here probably a bad FPR and been adding 2 stroke oil and it hasn't done it in a while.
I use the stuff in a blue jug from Wal-Mart TC-W3 and mix it 200:1

Does it make the "clacking" sound or just shutter when you drive?

If its just a FPR issue then I have an LBZ CP3 im going to swap in with a regulator soon, just a matter of getting around to it

 

[six5creed]

Mine sounds more like an air wrench on about half trigger when it does it.

 

[cstephens93]

Hmm, Not sure if mine makes that noise lol


Of course all these problems start popping up after I pay my truck off

 

[Chevy1925]

you may have an injector not sealing against the copper washer anymore.

 

[cstephens93]

you may have an injector not sealing against the copper washer anymore.

Thanks for the suggestion.

It sounds like its coming from the passenger side, but not sure yet.

I'll have to inspect it pretty closely when I get a chance

 

[Burn Down]

As James mentioned ck the hold downs. Also have you protected/inspected the harness at the Ficm, Ice picked 2 and 7 or done the gm harness reroute on 2 & 7?

 

[cstephens93]

As James mentioned ck the hold downs. Also have you protected/inspected the harness at the Ficm, Ice picked 2 and 7 or done the gm harness reroute on 2 & 7?

When I bought my truck back in 2013, I replaced part of the harness on the injectors, but there may be some wear from rubbing near where I have the EGR delete tube running

 

[Burn Down]

It sounds pretty intermittent. Original injectors?

 

[cstephens93]

It sounds pretty intermittent. Original injectors?

Yes sir!

Same injectors as far as I've ever been told.

Is there anyway to accurately figure out which number injector the issue is coming from?

I'm in no position to replace all of them at once

 

[Blackmax123]

Have you checked balance rates or return rates?

 

[cstephens93]

Have you checked balance rates or return rates?

Yup, the balance rates alone dont show much. However, I need to compare the rates to the fuel return rate

 

[Burn Down]

Did you ck the ficm harness and ice pick 2 and 7 yet? I would start there cheap and easy enough.

 

[cstephens93]

Yeah I checked, nothing to note.

But I am going to wiggle the harness around some more and see if I can get it to fault on purpose

I checked my main injection fuel rate and its at 6mm3 at idle

Then my balance rates read in park

Injector 1 -1.2
Injector 2 1.6
Injector 3 0.6
Injector 4 -0.8
Injector 5 1.7
Injector 6 0.6
Injector 7 -0.6
Injector 8 -2.1

Then my balance rates read in gear

Injector 1 -2.4
Injector 2 1.2
Injector 3 0.0
Injector 4 -0.8
Injector 5 7.3
Injector 6 -0.5
Injector 7 -1.4
Injector 8 -3.4

 

[cstephens93]

I also need to go back and check these again because the above readings were on a 90hp performance tune and the AC was on,

So i need to switch over to the stock tune and check with the AC off

 

[cstephens93]

Was given a trouble code this weekend


Code: P1235
Modules: ECM
Description: Injector 5 Output Circuit

I'm thinking this issue im having is definitely more to do with a connection/wiring issue like everyone has mentioned above

 

[Burn Down]

Did you ice pick 5 yet?